sync: add WIFI_CREDENTIALS protobuf, ModelType, and preference

sync/protocol/proto_enum_conversions.h

 // Copyright 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef SYNC_PROTOCOL_PROTO_ENUM_CONVERSIONS_H_
 #define SYNC_PROTOCOL_PROTO_ENUM_CONVERSIONS_H_
 
 // Keep this file in sync with the .proto files in this directory.
 
 #include "sync/base/sync_export.h"
@@ skipping 18 matching lines @@
 SYNC_EXPORT_PRIVATE const char* GetBrowserTypeString(
     sync_pb::SessionWindow::BrowserType browser_type);
 
 SYNC_EXPORT_PRIVATE const char* GetPageTransitionString(
     sync_pb::SyncEnums::PageTransition page_transition);
 
 SYNC_EXPORT_PRIVATE const char* GetPageTransitionRedirectTypeString(
     sync_pb::SyncEnums::PageTransitionRedirectType
         redirect_type);
 
+SYNC_EXPORT_PRIVATE const char* GetWifiCredentialSecurityClassString(
+    sync_pb::WifiCredentialSpecifics::SecurityClass security_class);
+
 SYNC_EXPORT const char* GetUpdatesSourceString(
     sync_pb::GetUpdatesCallerInfo::GetUpdatesSource updates_source);
 
 SYNC_EXPORT const char* GetUpdatesOriginString(
     sync_pb::SyncEnums::GetUpdatesOrigin origin);
 
 SYNC_EXPORT_PRIVATE const char* GetResponseTypeString(
     sync_pb::CommitResponse::ResponseType response_type);
 
 SYNC_EXPORT_PRIVATE const char* GetErrorTypeString(
@@ skipping 19 matching lines @@
 
 const char* GetDisplaySizeString(
     sync_pb::ChromeSyncFolioInfo::DisplaySize display_size);
 
 const char* GetFetchErrorReasonString(
     sync_pb::ChromeSyncClip::FetchErrorReason fetch_error_reason);
 
 }  // namespace syncer
 
 #endif  // SYNC_PROTOCOL_PROTO_ENUM_CONVERSIONS_H_